It is a lizard that appears to have adapted to the hazardous habitat of the Capital of the Unreturned, growing up in their eggshell and using it as a shield to keep them safe even from the "iron rain" of the 6th layer. They are quite ferocious, but edible, and can be eaten without too much preparation.
According to Lyza, they will continue to grow endlessly for as long as they live and they appear to have a ridiculously long lifespan. The legendary Delver claims to have encountered one with a towering frame of 30 meters. This Emperorshell was strong enough that even the White Whistle Delver Lyza, cherished for her phenomenal fighting ability, seemingly failed to take it down, leading to her naming it "Emperorshell" following her unsuccessful hunting.
- According to Lyza, the juvenile form of the Emperorshell is very tasty and whether or not the same goes for the one of enormous size she encountered too is a question she would leave for those who come after her to answer.